1. Field of the Invention
This invention relates in general to a vertical takeoff and landing airplane, and in particular to an airplane which takes off and lands on its tail section with its fuselage pointed up.
2. Description of the Prior Art
One need for a vertical takeoff and landing airplane is in the area of unmanned aerial vehicles. These airplane need to be able to be launched and landed on a ship or other place which would not have an airstrip. An unmanned airplane contains surveillance equipment, such as television cameras and night vision equipment. An operator will control the unmanned airplane by the use of radio signals
In the prior art, these airplane were large versions of conventional radio control model airplanes. They can be launched from a ship by using a catapult. However, it is difficult to land the unmanned airplane. Operators sometimes use nets to try to catch them as they approach the ship.
Full scale manned vertical takeoff and landing aircraft are available. These include helicopters, a tilt wing propeller aircraft, and also jet airplanes with deflecting nozzles. These types of vertical takeoff and landing aircraft have not been efficiently scaled down to be used as an unmanned aerial vehicle for surveillance. Generally they have too much complexity, making them too expensive.
One type of vertical takeoff and landing airplane proposed in the past is known as a "tail sitter". A tail sitter airplane takes off and lands on its tail section, with its nose pointed upward. In the 1950's and 1960's, full scale manned tail sitting airplane were built. Some utilized jet propulsion. Others used propellers. There are many variations suggested in the patented art for tail sitters.
One problem with a tail sitter airplane is how to handle the counter torque caused by the rotating propeller during takeoff and landing. Without some means, the fuselage would spin in reverse to the rotating propeller. This is handled generally by using counter rotating propellers. One rotates in one direction, while the other propeller rotates in the opposite direction. This eliminates the counter torque. However, mechanical complexity results.